Method for reclamation of absorption oil



July 21, 1936. Y P. B. RENFREW ET AL 2,043,140

METHOD FOR RECLAMATION OF ABSORPTION OIL Filed Nov. 16, 1931 7 Sheets-sheaf 1 c aezfm' paa/ fl gar/fizz & Lear/a .Z'. Nansi July 21, 1936. P. B. RENFREW El AL 2,048,140

METHOD FOR RECLAMATION OF ABSORPTION OIL Filed Nov. 16, 1931 7 Sheets-Sheet 2 ff 12 z July 21, 1936. P, B. RENFREW ET AL METHOD FOR RECLAMATION OF ABSORPTION OIL Filed Nov. 16, 1931 7 Sheets-Sheet 3 y 1936- P. B. RENFREW El AL 2,048,140

METHOD FOR RECLAMATION OF ABSORPTION OIL Filed- Nov. 16, 1931 7 Sheets-Sheet 5 I Ms July 1936- P. B. RENFREW El AL 2,048,140

METHOD FOR RECLAMAI'ION OF ABSORPTION OIL Filed Nov. 16, 1931' 7 Sheets-Sheet 6 July 21, 1936. P. B. RENFREW ET AL METHOD FOR RECLAMATION OF ABSORPTION OIL '7 Sheet-Sheet 7 Filed Nov. 16, 1951 xi $67229 &

Patented July 21, 1936 i 'UNllfED; STATES METHOD FOR RECIJAMATION F ABSORPTION OIL Paul B. Renfrew and Leona Marsln Fort Wayne, Ind., assignors to S. F. Bowser & Company, Inc., Fort Wayne, Ind., a-corporation of Indiana Application November 16, 1931, Serial No. 575,198

8 Claims.

This invention relates to the reclamation of .oils such as absorption oils, also any other petroleum (hydrocarbon) oils contaminated with'impuritiessuch as parafiin wax, carbon, sludge and the like, dry cleaners solvent, and solvents containing greases whose boiling points are within the .boilingrange of the solvent and other petroleum hydrocarbon oils.

One of the objects of our present invention is 3 to provide a process and apparatus. for the rec-. 'lamation of the hereinbefore described oils and solvents forefiectively removing therefrom carbon, coke, paraflin wax, dust, crude oil,v dirt, grease, acids, acid compound, moisture, sludge, unstable compounds, heavy fractions and undesirable foreign constituents, and whereby the reclaimed oils and solvents'will be more stable, or more resistant to headlight and oxidation, and will be as good as, if not better than such oils or solvents when new and'uncontam'inated.

Yet another object of our invention is to provide an improved process and apparatus for the economical reclamation and reconditioning of' absorption oils and particularly in theadapta-.

. tion of the process to the reclamation of absorption oils used in the process of extracting gasoline from natural gas "whereby a. practically continuous process is produced, not only 'for the.

reclamation of the absorption oil itself, but also in the 'use'oi the reconditioned or reclaimed ab-. sorption oil in the gasoline absorption process.

.Yet another object o'fourinvention resides in an improved process and apparatus for. the reclamation of solvents used in dry cleaning plants and solvents used in the Washing of metal parts.

Yet another object of our invention resides in the improved process and apparatus for the reclamation of any petroleum oil which is contaminated with impurities such as paraifin wax, car-- bon, sludge andthe like.

Yet another object of our invention resides in the provision of an improved process and apparatus for the reclamation of solvents containing greases whose boiling points-are within the boiling range of the solvent itself. 1

Yet another object of our invention resides in providing a reclamation process and apparatus for oils and solvents which comprises heating the oil or solvent body to a temperature whereby to distill oif the desired fractions While converting the undesirable constituents into compounds whichare not soluble in the oil body and which will notdistill ofi at the selected distillation tem-. perature of the desired hydrocarbons.

These and; other objects of ourinventionwill be apparent from a perusal of the following. specification when taken in connection with the following drawings which show a preferred form of apparatus for carrying out our process and wherein:

Fig. l'illustrates one form of our'improved apparatus for carrying out the process of. our invention;

Fig. 2 is a sectional view of the evaporator used in such apparatus;

Fig. 3 Ba section on line 33 of Fig. 2;

Fig. 4 is a section on line 44 of the evaporator shown in Fig.1;

'Fig. 5 is a perspective view of the member for directing thesteam and heated air into the evaporation chamber of the evaporator;

Fig. 6 is 'a sectional view .of the water separa In carrying out our process, we project heated air and steam (the air ,being in comparatively large volumes) through the body of oil or solvent heated to'the proper working temperature and containing a desired quantity of monobasic alkali, such' as 'NaOI-I, KOH, LiOH, RbOI-I, CsOH By means of this treatand other equivalents. ment, the desired fractions of the oil or solvent are evaporated and thereafter recovered by condensation. Theheated air and steam keep the oil or solvent body in a constant state of agitation, increase the surface exposed and thus in-' crease thezrate of evaporation. In addition, theair and steam rising out of the oil or solvent body; with desired velocity, act as carriers for the hydrocarbon vapors to carry them over into the condenser for further treatment. So, also, the

pressure of the heated air and steam in the evap-,

oration chamber above the oil or solvent body acting in accordance with Daltons law of partial pressure, lowers the evaporation point of the heated oilor solvent so that the evaporation can be carried out under more moderate tempera-' tures with the consequent elimination of the vaporization of the parafiiin waxes and heavy ends.

The heated air oxidizes certain constituents of.

the oil, resulting in some polymerization. The caustic soda wet or moistened by the steam forms sodium compounds.

The caustic soda :function is decidedly advantageous because the.

'peratures which carry over the desirable constituents.

The steam keeps the caustic soda in a soluble,

reactive condition. In addition, the steam is a' good carrier of hydrocarbon vapors and the heat' of solution'of caustic soda is exothermic. The steam also reduces the boiling points and thus, eliminates the possibility of cracking.

The air is a good carrier of hydrocarbon vapor and gives velocity to the hydrocarbon 'vapor stream. Air has a direct chemical action on'the oil; It oxidizes certain constituents of the oilor.

solvent increasing their molecular weight, thereby retaining themlin the evaporation chamber and preventing them passing over withthe desiredhydrocarbon vapors. The air reduces the amount of steam required to producethe evaporationand reduces the amount of steam required to give velocity tothe vapor stream. This air is considerably less expensive to heat to the required working temperature than is waterto produce steam for the same purposes.

The combined action of-the'air and steam on the heated oil or solvent body thushasmany.

advantages and-desirable results not inherent in the use of air alone, or steam alone. Theprocess of the present invention is concerned with evaporation, and not true boiling. The steam heated air passing through the oil or solvent immensely increases the evaporation surface'and the com bined steam and hot air pressure in the evaporation chamber above the oil body reduces the evaporation point of the oil in accordance withv Daltonsi theory of partial pressure. 'Furthermore, the moisture due to the pressure of the steam in the evaporator, combined with the oxy-- gen of the air, tends to promote oxidation. The

rate of hydrocarbon vapor yield,'i. e., the rate of yield of-the reclaimed oil;or solvent, is directly proportional to'the vapor volume passedthrough the oil, other factors being equal.

By the utilization of the heatedair and steam in the evaporation chamber in'the manner aforesaid, the temperatures used can be moderatedso as to oxidize and polymerize theparaflin waxes,

the heavy ends, etc., without. volatilizing them, and the products of reaction with the caustic sodawill be retained in the evaporation chamber and will not be carried over with the hydrocarbon vapor stream. The hydrocarbon vapor stream passing from the evaporation chamber goes into the condenser where the steam iscond'ensed into water and the hydrocarbon vapors into oil or solvent. The air passing on is washed to remove any entrained: hydrocarbons and is thereafter'free to atmosphere, while the combined oil and water is passed through a separator sothat theoil is separated out and is then further treated to remove water and moisture therefrom. Theresulting product is a moisture-free oil or solvent from which all undesirable impurities and con-- taminations which were present in the liquid before treatment have been removed. and which In addi- 'tion, theair assists in oxidizing the paralfin wax. 35;;

reclaimed oil or solvent is equal to and in some instances, superior to the same solvent or oil prior to becoming contaminated. In the accompanying drawings we have illustrated'an apparatus for carrying out-our process. 'In general, 5 this apparatus comprises an evaporator'z wherein'the body of oil or solvent is heated to the proper working temperature by any" desired means, and wherein steam and heated air are forced through the body of oil or solvent into which has previously been introduced a predetermined' quantity of mono-basic alkali of the character hereinbefore described. The reaction withinthis evaporator is such that the desired hydrocarbon vapors are carried oil by the projected current of steam and heated air to a heat exchanger 4 hereinafter described, thence through a condenser 6 where the steam and hydrocarbon vapors are condensed. The water and condensed oil or solvent in intermixed state are then passed to the water separator 8 in which the oillor solvent is separated from the water, and then the oil or solvent is passedthrough an entrained moisture separator ill for removing all water or moisturecontent therefrom, and finally the reclaimed solvent or oil ispassed either to .a storage tank l2, or is returned to. the system inwhichit istobeused. With particular reference ,to Figs". 1 to.5, inclusive, the preferred form of our evaporator 2 i comprisesv a tank-like inner member I4 provided with a criss-cross or lattice arrangement of openendedpipes passing completely therethro-ugh to provide heat exchange passageways through; which steam, hot oil or other heating fluid may flow for the purpose of heating the dirty or con taminated oil or solvent in the tank to desired a let 26 through which flows the hydrocarbon vapor stream resulting from the evaporation of the body of oil or solvent in the tank. As ,willbehereinafter describedthis vapor stream is caused by the projection of heated air and steam under pressure through the oil or solv'ent body'in the tank in sucha manner that in passing through' and out of the liquid body the moving column of steam' and heated air acts as agitatonfoxidizer and finally as a carrier to convey the desired hydrocarbon fractions out through the-outlet 26. The

bottom of the tank' l4 terminates in conical or converging'walls Z8 ending in athroat 3fl'pro-' viding an aperture 32 at the bottom through which the contents of the evaporator tank l4 may be drained or throughwhich thelre'sidualsludges and undesirable-impurities within 'the' tank may be discharged at proper intervals. The 7 bottom of the tank opposite the mouth It'llis'provided with means for dispersing and distributing the incoming 'Stream of heated air and steam whereby to cause a substantially uniformagitation of the heated dirty oil in the tank for the purpose of' augmenting the evaporation as hereinafter described and also for the-purpose of preventing the oil, or solvent body from being blown upwardly and into the hydrocarbon outlet 261 To this end the conical walls '28 enclose an up standing partition 34' carrying a plurality'of bafsho-wn, any desired means for heating the oil or fies .36 which .may be perforated or alternatively. may be .spaced as at 38 from the conical wall '28 for the above described purposes. Obviously any other type of bafiie construction or any desired means for appropriately and effectively creating a uniform and effective agitation throughout the dirty oil or solvent body may be used.

Very effective means for economically heating the dirty oil or solvent body within the tank I4 tothe required working temperature for effectingsevaporation of the desired hydrocarbon fractions, 'may be provided by the use of a construction'such as that shown in Fig. 2 of our drawings which show the details of one type of evaporator.

.In' this construction the inner tank wall I 4 is shown'as surrounded by a wall member 40 'to provide an inner jacket or heating chamber 42 surrounding and enclosing this central tank. We prefer to fill this inner jacket 42 with steam as the heating medium, through pipe 43 coming from any appropriate source and at a desired temperature; In the use of our device in connection with an absorption system for the extraction of natural gas from gasoline, the steam jacket may beconnected to the steam plant of the absorption system,in which case the jacket will be heated to approximately 340 to 360 F. It must be obvious, however, that the temperature of this jacket is dependent upon the nature of the oil or solvent being reclaimed. For instance, where we are reclaiming heavier oils, the temperature of the steam might necessarily have to run. as high as 370 F., or even more. It will also be apparent that instead of having the steam jacket 42 as solvent body may be utilized. Even heated oil itself may be used instead of the steam in the chamber 42, in which case the heated oil would have the desired hereinbefore stated range of temperature. In the construction illustrated, the steam within. the jacket 42 is adapted to pass directly through the criss-cross open-ended pipe l6 whereby more efiectively to heat the dirty oil or solvent within the central tank I4.

In certain instances we also provide the evaporator with an outer jacket. In this construction the jacket walls 40 are enclosed or surrounded by anouter wall 44 toprovide an outer jacket or heating space 46 surrounding the inner jacket 42. In certain installations this jacket may be utilized to heat condensed water flowing from the condenser heat exchanger forming. another part of this apparatus as is hereinafter described. Alternatively, this outer jacket may be eliminated l and the steam to be utilized may be taken directly When thisouter from the steam line or boiler. jacket isused, it is adapted to be connected to aninlet pipe 48 connecting with the water coil outer jacket 45 as well as the bottom part of jacket 42,-is closed by means of "a wall 69 arranged at the bottom of the tank and-surrounding the discharge nozzle 32. The. evaporator is en-' closed by suitable heat-insulated walls;

"Means is provided for introducing heated air;

and steam under pressure into the bottom of the tank 54 in such a manner that the heated air and steam will be projected through the heated oil or solvent body for the purposes hereinbefore and hereinafter described. While this heated air and steam may be injected into the oil or solvent body in any desired manner in the preferred form of my evaporator, it is introduced in the following manner: The outer jacket 45 is provided'with means for conducting the steam which accumulates at the top of this jacket, downwardly to the bottom of the evaporator and it is associated with a connection from an air blower or other source of air pressure. In the construction illustrated, a sheet metal strip 52 shown in perspective in Fig. 5 and formed of any desired channel shape is soldered, welded, or otherwise .afiixed to the outer surface of the jacket wall 40. The top 54 of this channel member 52 is left open so that steam entering can readily flow down the passageway 55 formed thereby. The bottom portion of this channel member 52 is bent inwardly to lie parallel with the conical wall portion 28 of the tank as at 58, and at its lowermost edge is provided with a nozzle which is arranged so as to deflect the steam upwardly into the mouth 32.

The blast of air associated with the steam is provided by an air blower 62 run by motor 64 and which blower connects by means of suitable piping 66 with the bottommost portion of jacket 46 and in such a manner that the entering air will join with the steam and will be heated by such steam and by the jackets 46 and 42. This co-mingled hot air and steam will then be forced under pressure through the channel member 56 out through the nozzle 60 and thence upwardly through the mouth 32 Where it will be projected through the oil or solvent body, the bafiles 36 effecting the even distribution of the steam and air through the body in the manner hereinbefore described.

The inner tank I4 contains the dirty oil or solvent to be reclaimed. The dirty oil or solvent enters the apparatus through a pipe 68 shown in Fig. 1 and will thence flow to the liquid level flow valve mechanism 10 of any well-known designand thence by means of pipe 12 to the bottom portion of the central tank l4. The top of the inner tank I4 is connected by a pipe 1'4 with the liquid level device and the arrangement is such that the oil is maintained at the desired level within the tank i4. Any desired means may be employed for delivering oil or solvent through pipe 68 to the evaporator. In addition there is provided a sludge valve .80 provided with'a noze' zle 82 and a control 84 for emptying the contents to the tank l4 when desired.

The oil or solvent may be introduced into the evaporation chamber 54 at any desired temperature. In some cases the oil or solvent being reclaimed will come into the evaporator at atmospheric temperature. In processing the heavier fractions, it is desirable to have the oils enter at an elevated temperature. These temperatures will vary according to the oil or solvent being reclaimed and in accordance with the 10- cal conditions where the equipment is being used. For instance, when the apparatus is used for the reclamation of absorption oils and in connection with absorption sysmms for the extraction of gasoline from natural gas, the commonly used temperature of such systems or plants the heat exchanger 4 shown in detail in Fig. 8

of the drawings. This heat exchanger comprises a pipe 88 of suitable dimensions connecting with pipe26 and enclosed within heat insulating walls 90. A coil pipe 92 extends practically the length of the heat exchange pipe 88 and the end-94 of this coil 92 connects with theliquid inlet pipe 48 so as to pass heated water'to the outer jacket 46. The other end of coil 92 has a connection 96 with a pipe 98, (see Fig. 1,) which in, turn connects with a waterpump I00, whereby water is pumped through the coil of the heat exchanger 4 where the water is heated to high temperature and then passed into the outer jacket 46 where it is heated by jacket 42-and its evaporation is completed. The outer end of the heat. exchange pipe 88 connects'with an elbow I02 leading to the condenser 6. This condenser comprises a cylindrical housing forming ,the chamber I04 in which is located a,coil;l00 which constitutes the cooling coil for condensing the hydrocarbon vapors and steam to form the reclaimed oil and water and which flows out of the exhaust pipe I08 leading to the free water separator 8 shown indetail in Fig. 6 of the draw-' 'ings.

The coil I06 is connected. to any suitable cold water supply. This pipev I I0 has a branch connection IIZ tothe water sealed box of the free water separator shown in Fig. 6, for 'furnishing tank I32 with water as hereinafter described. The'other end of coil I06 is provided -with a connection II4 to a pipe I I6 1eading to heating coils scribed.

The condensed vapors from the condenser are which will be hereinafter dedelivered into the free water separator18 as air,;

oil and water. By reference to Fig. fi'it will be seen that'this free water separator comprises a tank II8 through the top of which enters pipe I08 through which pass the condensed hydrocarbon vapors'and steam coming from the condenser. The chamber I I8 is provided with internal partitions I20 and I22 providing a liquid receptacle I24 into which the entry oil, water and air flows from pipe I08 and also a separate outlet chamber.

The airpasses out of tank I I8 through apipe I26 which terminates in a perforated nozzle I28 adapted to be submerged in a body of water I30 in a water-wash tank I32 preferably mounted-on top of tank II8. Any traces of mist in the air are removed by the body of water I42 before the air exhausts from pipe I34. A water leg I3Iiconnects the water-wash tank with the bottom of the free water. separator tank II8. I

The oil and the water entering tank I I8 settle therein and the free water precipitates to the'bot tom of the tank. The super-ambient oil or solvent flows under the bafile I20 and thenrises tothe pipe I38 which connects with the entrained moisture separator. A sight glass I40 is provided'for this pipe I38. The bottommost portion of tank I I8 has conical walls terminating in the nozzle I42 controlled by valve I44, for emptying the contents of this tank when desired. In addition, the tank is provided with an internal pipe'I46 which opens near the bottom of the tank and rises upwardly therein tothe point I48 where it passes through the walls of the tank H8 and connects with thevertical pipe I50 which pipe at its upper end has a vent outlet I52 to atmosphere and which 'at its bottom end connects to the drain system.

'so that the 'oil is sprayed onto a body of waste.

moisture are formed into relatively larger 'globdispensed with.

The ,oil leaving the free water separator by-l0 means of the'pip'e I 38 contains some entrained moisture and it is therefore necessary to further treat this oil to remove it. Accordingly theoil flowing through pipe I 38 .passes into the entrained moisture separator I0 which is shown in detail in Fig. '7. This comprises'a' casing I56 into which the pipe I38" projects. The pipe is provided with adistributing or spray nozzle I58 I60 mounted on aforaminated support or screen I62; The oil-passing'through' this waste discharges into a pipe I64 which terminates near the bottom of the tank I56. By passing this oil through the'waste the finely divided particlesof ules ofmoisture which precipitate and pass to the bottom of the tank. The oil rises and stratifies above the water level. Tank I56 is provided with a heating coil I66 likewise connecting with pipe -I I6 whereby heatedwater from the condenser is forced through this heatingcoil I66. A water discharge pipe I68 has its lower'end open to the bottomof the; tank I56. The upper end of the pipe I 68 connects with the vertical water pipe I50 hereihbefore described. The heating coil in the tanks 8 and I0 assists in breaking up' the formation of emulsions therein. Tank I56 is likewise provided with a water leg I10 for maintaining the proper water level, and with a valve con-. trol outlet I12. .In addition the upper portion 'of'the tank is provided with a hinged cover "4.

Tank I56 is provided with an oil discharge pipe I'I6 which communicates preferably with a storage tank I 2. The pipe I56 is provided with a sight glass I I8 with 'a riser leading to atmosphere. The storage tank I2 is preferably provided with a float'con'trol valve leading to a pumping unit' I 80 which leads back to the source of use. In instances where it is not necessary to force the. reclaimed oil under pressure'back to the system. in which it is to be used, the oil can flow by gravity in which case the small storage plant I2, the float control valve and the pump I80 can be By reference to Fig. 1 of the drawings it will be seen that the pipe I I6 coming from the condensercoil I06 and the interconnected hot water'- 'coilsrl54 and I66 connect. to a pipe I82 (see Figs.

land-6). H 7

As hereinbefore stated, our process is particularly adaptable to the reclamation of absorption oils used in natural gasoline plants in the recovery and extraction of gasoline from natural gas, and we therefore will utilize this specific adaptation of our invention for the purpose of illustrating its advantageousfeatures in connection with a specific industry. -It is to be understood, however, that the hereinbefore described adaptation of our method to the reclamation of absorption oils is not by way of limitation or restriction of the inventionto such specific use. V Absorption oils are used for the extraction of gasoline from naturalgas and for the extraction of benzol from coal tar gas. In the case of gaso line extraction these absorption plants are'generally located along the pipe line which conveys the natural gas from the field to the market. In these extraction systems the gas is passed through the absorption oil where a certain percentage of the gasoline in the gas is absorbed by the oil. The gasoline content is then removed from the absorption oil. The extracted gasoline is passed on to a separate container while the oil is re-used in the absorption system. Thus the absorption oil is being continually circulated through the system for the extraction of the gasoline from the gas. From this continuous use the absorption oil becomes contaminated with impurities such as carbon, coke, parafiin wax, dust, crude oil and other impurities to such an extent that eventually it can no longer be used. These absorption oils, while comparatively cheap, after becoming so contaminated are rendered unfit for further use in such absorption systems. Heretofore they have been thrown away,

In the utilization of our invention for the reclamation of absorption oils and particularly as applied to natural gasoline absorption plants, the present apparatus is preferably connected into the system in such a manner as to continuously receive absorption oil from the absorption system at elevated temperatures. This oil will, of course, have had the gasoline fractions removed therefrom in the natural gasoline absorption plant. In other words, our present apparatus, when used for reconditioning absorption oil used in natural gasoline absorption plants, is installed so as to receive oil after the gasoline has been removed. By our invention we recondition this oil and return it to the absorption system in the same or in better condition than new oil, and in such a way that the cost of reclamation is very small, being, in fact, from one fourth to one half below the cost of new oil which at the present market prices is the lowest in the history of the industry.

During operation there is an accumulation of heavy ends, sludge and other impurities in tank l4. At regular intervals, depending on conditions and degree of contamination of the oil being treated, this sludge will have to be drained out of tank l4.

During these cleaning periods it is necessary to close valve in line 68 and stop motor 64. Draining is accomplished by means of valve 82. After the draining is completed valve 82 is closed. Tank I4 is then filled to the proper level by opening a valve in line 68. A chemical charge hereinbefore described is then added to the oil in tank [4 through opening 20 by removing cover 22. After replacing cover 22 the motor 64 is started andthe reconditioning system is again in operation.

Our process is advantageously adaptable to the reclamation of cleaners solvents and/or solvents which carry in addition to the unstable petroleum compounds, quantities of greases, the boiling points of which are within the boiling range of the solvent. So also it applies to the reclamation of solvents used in washing metal parts during the processing and to the reclamation of any petroleum hydrocarbon oil which is contaminated with impurities such as carbon, wax, heavy ends, dust, dirt, sludge and similar impurities.

It will be apparent that by the utilization of our improved process and apparatus we are enabled to economically reclaim and recondition various types of oils and solvents which have become contaminated and rendered impure during their use in various commercial plants and systems. By our process, these oils and solvents are treated at a very low cost to remove all such objectionable impurities such as dust, dirt, carbon, sludge, metal parts, acids and acid components, paraffin waxes, heavy ends and unstable unsaturates and moisture so that the reclaimed liquid is in most cases superior to and certainly the equal of the original solvent or oil prior to becoming contaminated and impure.

Having thus fully described our invention, what we desire to secure, by Letters Patent is:

1. The process of reclaiming liquid petroleum hydrocarbon solvent having boiling points not above that of absorption oil which comprises mixing the liquid solvent with a mono-basic alkali, confining a body of said mixture in a treating and distillation zone, passing air and steam through the body, with suificient volume and with sufficient speed to produce marked agitation of the mixture so that the steam, air and alkali come into intimate contact with the liquid solvent thereby to vaporize the desirable portion of the contaminated solvent, collecting and condensing the vapors and separating the condensed solvent from the water resulting from condensation of the steam.

2. The process according to claim 1 wherein the solvent being reclaimed has become contaminated through use in the recovery of natural gas gasoline by the absorption system.

3. The process according to claim 1 wherein the solvent being reclaimed has become contaminated through use in dry cleaning.

4. The process according to claim 1 wherein the solvent being reclaimed has become contaminated through use in cleaning metal parts.

5. The process according to claim 1 wherein the temperature is maintained around 340 to 370 F. in the distillation step.

6. The process according to claim 1 wherein the alkali is caustic soda.

7. The process according to claim 1 wherein the air is heated before injecting it into the solvent body.

8. The process according to claim 1 wherein the solvent to be reclaimed contains greases of boiling points within the boiling range of the solvent.

PAUL B. RENFREW. LEONA E. MARSH. 

